This article is more than 5 years old. Information may no longer be current.
Cross-linking may halt hyperopia progression after corneal refractive procedures
LAS VEGAS — Collagen cross-linking with riboflavin may stop hyperopia progression in patients who have undergone radial keratotomy or laser ablative procedures, according to Brian S. Boxer Wachler, MD.
At the AAO meeting here, Dr. Boxer Wachler reviewed the results of a study evaluating whether corneal collagen cross-linking with riboflavin, or C3-R, can stabilize the progression of hyperopia in patients with previous refractive surgery.
The study included eight eyes of six patients that had documented progression of hyperopia after undergoing RK followed by a laser ablation procedure, either LASIK or surface ablation.
After the cross-linking procedure, hyperopia progression was halted in all eyes, Dr. Boxer Wachler said. No eye had more than a 1 D change of sphere or cylinder after the C3-R treatment, he said. There was little change in uncorrected visual acuity, best corrected visual acuity or keratometry after the treatment, he said, although corneal topography showed some steepening. No change in endothelial cell count was seen.
“These early results are suggestive that there may be stabilization occurring, and if follow-up in the long-term really shows improvement, this is going to be a nice treatment to offer patients that are suffering from progressive hyperopia,” Dr. Boxer Wachler said.
Following are other highlights of cornea/external disease sessions from the AAO meeting. Most of these items appeared first as daily coverage of the meeting on OSNSuperSite.com.
|
Image: Moskowitz A, OSN |
Laser-created Intacs channels improve results
Femtosecond laser-created channels for insertion of Intacs (Addition Technologies) may result in better visual outcomes than mechanically created channels in patients with ectasia or keratoconus, according to Sheraz M. Daya, MD.
Dr. Daya reviewed the results of a retrospective study including 32 eyes of 30 patients who underwent Intacs channel creation with the IntraLase FS femtosecond laser. These were compared to 17 eyes of 15 patients who underwent conventional mechanical channel creation.
Initially, the laser group suffered a decrease in visual acuity. At 6-month follow-up, however, 66.7% of the laser group had achieved BCVA of 20/40 or better. Only 8% of the control group achieved this outcome. The laser group also achieved great improvements in keratometry and astigmatism, according to Dr. Daya.
“IntraLase is more effective than conventional implantation, and I think a lot if it is due to our nomogram change and better diameter of ring channel,” he said.
Keratoprosthesis effective with proper postop management
Keratoprosthesis is a viable alternative to standard penetrating keratoplasty in certain types of patients prone to repeated graft failure, according to Kathryn Colby, MD, PhD.
Dr. Colby said that postoperative care is crucial to success with the Boston K-Pro Type 1 keratoprosthesis.
“The best category by far is noninflammatory graft failures in patients who have intact tear secretions and blink mechanisms,” she said. “These patients do extremely well with Type 1 Boston keratoprosthesis, both in terms of device retention and initial visual acuity improvement.”
The device is assembled by inserting a front plate through a fresh corneal graft and securing it with a back plate and a titanium locking mechanism. The host cornea is removed, and the device is sutured in place, Dr. Colby said.
In a recently published multicenter study including 141 patients, researchers found that 95% of eyes retained the device at 8.5 months follow-up, and 56% achieved visual acuity of 20/200 or better.
Although the device is relatively simple to implant, Dr. Colby said, “postoperative management is critical to success.” After surgery, patients should wear a bandage contact lens to keep the corneal tissue hydrated and reduce the risk of corneal melt. Topical steroids are also a mainstay of postoperative management, Dr. Colby said.
She also cautioned that IOP measurements become challenging once the device is in place. This is a particular concern because 60% of study patients had existing glaucoma, she said.
Ocular prevalence of resistant Staph increasing
|
|
The prevalence of ocular methicillin-resistant Staphylococcus aureus is increasing and must be continuously observed, according to a poster study.
Penny A. Asbell, MD, MBA, and colleagues analyzed current resistance patterns of ocular S. aureus. The researchers studied data provided by the Surveillance Network, an electronic database of strain-specific, qualitative and quantitative antimicrobial susceptibility tests reported by labs in the United States, according to the study.
The researchers found that of 13,978 cultures of ocular S. aureus samples tested from 2000 to 2005, 4,984 (35.7%) proved to be methicillin resistant, increasing from 29.5% of all cultured samples in 2000 to 41.6% in 2005, according to the study. Trends suggest that most ocular S. aureus infections will be methicillin resistant within the next few years, the authors said.
|
Image: Moskowitz A, OSN |
Topical phenytoin potentially effective against refractory corneal ulcers
Topically phenytoin powder may be an effective treatment for non-healing corneal ulcers, according to Jasvir Singh Grewal, MBBS.
Dr. Grewal and colleagues conducted a randomized, prospective study of 60 patients with corneal ulcers. All patient had been unresponsive to standard treatment, he said.
Of the 60 patients in the study, 30 received 15 days of treatment with topical phenytoin powder and bandages. The other 30 patients received bandages alone and served as a control group.
The researchers found that 86.7% of phenytoin-treated patients achieved complete pain relief and healing compared to 48% of control patients.
Mr. Grewal noted that he used phenytoin powder due to its availability, and that phenytoin gels or solutions should be investigated.
Fibrin glue may prevent pterygium recurrence
|
|
Sealing a conjunctival autograft with tissue adhesive may better protect against pterygium recurrence than absorbable sutures, according to Marjan Farid, MD.
Dr. Farid and colleagues conducted a retrospective review of 47 eyes of 42 patients with pterygium who were treated with excision and conjunctival autograft.
According to Dr. Farid, 27 grafts were sealed with Tisseel tissue adhesive (Baxter AG) and 20 with absorbable sutures. At a minimum follow-up of 6 months, the researchers found that pterygia had recurred in 20% of the suture group but in only 3.7% of the adhesive group ( P = .035), she said.
“It is unclear exactly why recurrence occurs. There is evidence to suggest that there is a transformation of the phenotypic characteristics of the conjunctival fibroblasts, which is triggered by ultraviolet radiation or inflammation. Certainly absorbable sutures can be very inflammatory, drawing in the ... cytokines that trigger recurrence,” Dr. Farid said.